An introducer for an expandable endovascular prosthesis having a self expanding stent has a distal prosthesis positioning mechanism and a proximal prosthesis retention mechanism. The proximal prosthesis retention mechanism includes a cylindrical sleeve adapted to retain the self expanding stent. A release mechanism extends proximally from the distal prosthesis positioning mechanism and exerts a force in the proximal direction on an interior surface of the self expanding stent to retain the self expanding stent in the cylindrical sleeve.